Fixation device for metaphyseal long bone fractures

ABSTRACT

A fixation device is provided which includes a proximal nail portion and a distal plate portion. The nail portion includes a flexible tapered section, and a rigid distal section larger in diameter and is adapted to be inserted into a medullary canal of a fractured bone. The plate portion has a low, narrow profile and includes three longitudinally displaced peg holes, each of which is adapted to orient a peg in a different orientation from the others. The plate portion is adapted to be positioned on the outside of a fractured bone when the nail portion is within the medullary canal. The device provides the benefits of both an intramedullary nail and a bone plate in a single device. The fixation device permits a minimally invasive treatment of the metaphyseal fractures that may otherwise be undertreated.

[0001] This application is a continuation-in-part of U.S. Ser. No.09/495,854, filed Feb. 1, 2000, U.S. Ser. No. 09/524,058, filed Mar. 13,2000, and U.S. Ser. No. 09/735,228, filed Dec. 12, 2000, all of whichare hereby incorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates broadly to surgical devices. Moreparticularly, this invention relates to implants for the fixation ofbone fractures, particularly in long bones such as the radius and tibia.

[0004] 2. State of the Art

[0005] Severe long bone fractures are often treated with plating. Inplating, a relatively large incision is made at the location of thefracture, musculature and tendons are displaced from the bone to exposethe bone surface, and a bone plate is fixedly attached to one or morepieces of the fractured bone in a manner which, ideally, supports andstabilizes the fracture for healing. Due to the relatively invasivenature of the procedure required to implant the plate, plating isgenerally reserved for fractures which cannot be treated with a lessinvasive method of immobilization.

[0006] Less complicated fractures are often treated with casting orwires. However, such conservative treatment may not provide thestabilization and support necessary for desirable recovery. Yet, theoperative procedure of plating is often too invasive for the relativenon-severity of the fracture. Moreover, conventional plating can resultin tendon irritation and skin necrosis. As such, many of the lessdisplaced fractures, and particularly metaphyseal fractures (fracturesat the end of the long bones), remain undertreated.

[0007] By way of example, a Colles' fracture, which results fromcompressive forces being placed on the distal radius bone, and whichcauses backward displacement of the distal fragment and radial deviationof the hand at the wrist, is treated with a dorsal plate when there is asignificant degree of displacement. However, a less-displaced Colles'fracture is commonly undertreated due to the hesitancy of physicians toprescribe operative and invasive treatment. If not properly treated,such a fracture results in permanent wrist deformity. It is thereforeimportant to align the fracture and fixate the bones relative to eachother so that proper healing may occur.

[0008] In addition, there is no minimally invasive procedure to treatfractures occurring at the metaphysis and that also provides the desiredimmobilization for such fractures.

[0009] Furthermore, there is no minimally invasive procedure to treatdistal radius fractures that provides the stability generally obtainedby more invasive procedures, such as open reduction and internalfixation.

SUMMARY OF THE INVENTION

[0010] It is therefore an object of the invention to provide a minimallyinvasive treatment which provides stabilization and support to long bonefractures.

[0011] It is another object of the invention to provide a minimallyinvasive treatment which provides stabilization and support tometaphyseal fractures.

[0012] It is a further object of the invention to provide a minimallyinvasive treatment which provides stabilization and support to fracturesoccurring at the metaphysis.

[0013] In accord with-these objects, which will be discussed in detailbelow, a fixation device is provided which includes a proximal nailportion and a distal plate portion, preferably horizontally andvertically offset relative to the nail portion by a neck portion, e.g.,such that the device preferably has a shape of an elongate ‘S’. The nailportion includes a tapered end which is flexible, and a relatively rigiddistal portion larger in diameter. For treatment of distal radiusfractures, the distal portion of the nail portion preferably includestwo cortical screw holes, and the plate portion has a low, narrowprofile and includes three longitudinally displaced peg holes, each ofwhich is adapted to orient a peg in a different orientation from theothers. The plate portion also includes a screw hole intended to receivea stabilization screw.

[0014] In use, a small incision is made in the skin, and the tapered endof the nail portion of the device is introduced percutaneously throughthe incision and through the fracture location into the medullary canalof the bone. The plate portion of the device is then maneuvered againsta surface of the bone, and a stabilization screw-is introduced to drivethe plate against the bone. Holes are drilled through the peg holes andinto the bone, and pegs are introduced through the holes to providestabilization and support for subchondral fragments. Optionally,cortical screws may be provided into the diaphyseal portion of the boneand into the cortical screw holes to further fixate the device.

[0015] The fixation device permits a minimally invasive treatment oflong bone fractures that may otherwise be undertreated.

[0016] Additional objects and advantages of the invention will becomeapparent to those skilled in the art upon reference to the detaileddescription taken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a proximal end top perspective view of the fixationdevice of the invention;

[0018]FIG. 2 is a distal end top perspective view of the fixation deviceof the invention;

[0019]FIG. 3 is a distal end bottom perspective view of the fixationdevice of the invention;

[0020]FIG. 4 is a top view of the fixation device of the invention;

[0021]FIG. 5 is a side elevation of the fixation device of theinvention;

[0022]FIG. 6 is a proximal end top perspective view of the fixationdevice provided with screws and pegs;

[0023]FIG. 7 is a distal end top perspective view of the fixation deviceprovided with screws and pegs;

[0024]FIG. 8 is a schematic view of a distal radius fracture; and

[0025]FIGS. 9 through 14 illustrate the method of the invention fortreating a metaphyseal fracture, particularly at the distal radius.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Turning now to FIGS. 1 through 5, a fixation device 10 for thetreatment of a fracture at an end of a long bone, i.e., a metaphysealfracture, is provided. The device 10 is preferably made of metal, e.g.,titanium or stainless steel, and includes a proximal nail portion 12 anda distal plate portion 14 that is preferably horizontally and verticallyoffset relative to the nail portion, e.g., by an ‘S’ shaped neck portion(or transition zone) 16 such that the entire device assumes a fixedelongate ‘S’ shape. As such, the nail portion 12 and the plate portion14 are fixed in a parallel, but non-coaxial relationship.

[0027] The nail portion 12 is preferably substantially circular in crosssection and includes a tapered flexible section 20, and a distalrelatively rigid section 22 generally substantially larger in diameter.The flexible section 20 is preferably slightly skewed laterally (e.g.,approximately 2° to 8°, and more preferably approximately 4°) relativeto an axis A extending through the plate portion and distal portion ofthe rigid section 22 (FIG. 4). The rigid section 22 preferably tapersinto the flexible section 20. The rigid section 22 of the nail portion12 preferably includes two cortical screw holes 24, 26 arranged alongthe length of the rigid section 22 and adapted to receive corticalscrews 28, 30 (FIGS. 6 and 7).

[0028] Referring to FIGS. 1 through 7, the plate portion 14 issubstantially rigid and has a low and narrow profile. The plate portion14 has a slightly concave bottom surface 32 and a slightly convex uppersurface 33. The plate portion 14 also includes three longitudinallydisplaced, threaded peg holes 34, 36, 38, each of which-is adapted toorient a peg (preferably having a threaded head portion) in a differentorientation from the others. In a preferred embodiment, the central peghole 36 orients a central peg 40 normal to the bottom 42 of the plateportion, while the other peg holes 34 and 38 are adapted to orient pegs44, 46 approximately forty degrees medially and laterally, respectively,relative to the central peg 40. That is, the pegs 40, 44, 46 are in afanned arrangement. Preferably the pegs 40, 44, and 46 are also orientedperpendicular relative to the longitudinal axis of both the nail andplate portions 12, 14. The plate portion 14 also includes a screw hole50 adjacent the neck portion 16 that is adapted to receive astabilization screw 52.

[0029] The device 10 is used as follows to treat a fracture 60 of thedistal radial bone 62 (e.g., a Colles' fracture), as represented in FIG.8. Referring to FIG. 9, first, a small incision 64 (generally less than2 cm) is made in the skin 66 on the dorsal side of the fracture 60. Fordistal radial fractures, the incision is preferably at a locationbetween the second and third extensor compartments and above Lister'stubercule 67 (a small bump a the distal end of the radius bone) so thatthe extensor tendons are not irritated by the incision or by theimplanted device 10. Referring to FIG. 10, a rongeur (not shown) is thenused to take small bites out of the bone at the broken end of the radiusbone so that a notch 68 is created preferably on the proximal side ofthe distal radius fracture 60. In addition, at least a portion ofLister's tubercule is removed to provide s surface for placement of theplate portion 14 at a location which will not cause tendon irritation.

[0030] Referring to FIG. 12, the tapered flexible section 20 of the nailportion 12 of the device is then introduced percutaneously through thenotch 68 and into the medullary canal 70 of the bone. The nail portion12 is pushed into the medullary canal 70 of the radius bone 62 until theneck portion 16 lies in the notch 68 created in the distal end of thebone and the plate portion 14 is positioned on the bone distal of thefracture and at the surface of the removed portion of Lister'stubercule. It is appreciated that reduction of the fracture (from thebone position of FIG. 8 to the bone position of FIGS. 9 through 14) mayoccur at this stage or at any other medically reasonable time during thefracture fixation process. During introduction into the bone and whenimplanted in the bone, the flexible section 20 of the nail portion 12will undoubtedly undergo some degree of bending, as the medullary canalmay not be perfectly straight and as the nail portion is bent at anangle. As such, the nail portion 12 operates to provide three pointfixation along the canal, with the proximal end 54 of the flexiblesection 20, the bent portion, and the distal rigid section 22 contactingthe wall of the medullary canal 70 of the bone. Moreover, the rigidsection 22 of the nail portion 12 provides a rigid intramedullary trusswhich enhances device stabilization.

[0031] Referring now to FIG. 13, a hole is then drilled into the bone 62in alignment with the stabilization screw hole 50 and a stabilizationscrew 52 is used to drive the plate portion 14 up against the bone. Withthe plate portion 14 stabilized by the screw 52, holes are then drilledinto the subchondral bone 78 through peg holes 34, 36, 38 (See FIG. 4).The pegs 40, 44, 46 are then introduced into the peg holes and the holesdrilled in the bone. The pegs 40, 44, 46 provide a framework forstabilization and support of bone fragments, including the radialstyloid and the volar dipunch, that is particularly effective in view ofthe fanned orientation of the pegs which follows the subchondralanatomy. Referring back to FIGS. 6 and 7, while the pegs preferably eachhave a threaded head 48 for engagement within the threaded peg holes,the shafts 49 of the pegs may be either threaded or substantiallysmooth. Moreover, omnidirectional pegs, such as described in detail inpreviously incorporated U.S. Ser. No. 09/735,228, may also be used toprovide a highly adjustable and customizable framework for bone fragmentstabilization. Briefly, the omnidirectional pegs are each inserted intoa respective peg hole, and are then be oriented into desired orientationwithin a permitted range. The pegs are then locked in the desiredorientation, e.g., with a set screw.

[0032] According to a practice well known with respect to intramedullarynails, a guide is then used to locate the positions for the screw holes24, 26 in the nail portion 12 (FIG. 13). Referring to FIG. 14, at leastone of the screws 28, 30 is preferably inserted through puncture holesin the skin, into the bone, and into screw holes 24, 26 to furtherfixate the device.

[0033] It will be appreciated that a device having such features asdescribed can be similarly used to treat other metaphyseal fractures oflong bones, e.g., tibial fractures, or combinations of metaphyseal anddiaphyseal fractures.

[0034] The device provides the benefits of both an intramedullary nailand a bone plate in a single device. The fixation device further permitsa minimally invasive treatment of long bone fractures that may otherwisebe undertreated.

[0035] When the device is used to treat a distal radial fracture, suchas a Colles' fracture, particular dimensions are preferred, though thedimensions of the device are not limited thereto. Such preferreddimensions include an overall length of approximately 4.2 inches, thenail portion has a length of approximately 3.56 inches, the plateportion has a length of approximately 0.65 inch, the bottom surface ofthe plate portion is preferably located approximately 0.29 inch above alongitudinal axis extending through the nail portion. It will beappreciated that the device may be provided in other relative dimensionsfor the treatment of other metaphyseal bone fractures, such as in thetibia.

[0036] There have been described and illustrated herein embodiments of afixation device and a method of using the device to treat bonefractures. While particular embodiments of the invention have beendescribed, it is not intended that the invention be limited thereto, asit is intended that the invention be as broad in scope as the art willallow and that the specification be read likewise. Thus, whileparticular dimensions have been disclosed, it will be appreciated thatother dimensions may be used as well. In addition, while titanium andstainless steel are the preferred materials, it will be understood thatother biocompatible materials can be used. Moreover, the flexibleportion may be made from a different material than the rigid portion,and the two portions may then be joined. Also, while the pegs arepreferably fanned at 45° relative to each adjacent peg, other fannedarrangements can be used. It will therefore be appreciated by thoseskilled in the art that yet other modifications could be made to theprovided invention without deviating from its spirit and scope asclaimed.

What is claimed is:
 1. A bone fracture fixation device, comprising: a)an elongate nail portion including a flexible section and a rigidsection relatively larger in diameter than said flexible section; and b)a relatively flat plate portion including a plurality of threaded pegholes, said plate portion being parallel to but not coaxial with saidnail portion.
 2. A bone fracture fixation device according to claim 1,wherein: said rigid section of said nail portion is substantiallystraight.
 3. A bone fracture fixation device according to claim 1,wherein: said flexible section is sized to be inserted into a medullarycanal of a radius bone.
 4. A bone fracture fixation device according toclaim 1, wherein: said nail portion is substantially circular in crosssection.
 5. A bone fracture fixation device according to claim 1,wherein: said flexible section has a tapered diameter along its length.6. A bone fracture fixation device according to claim 1, wherein: saidrigid section tapers in diameter into said flexible portion.
 7. A bonefracture fixation device according to claim 1, wherein: said nailportion include at least one screw hole.
 8. A bone fracture fixationdevice according to claim 1, wherein: said peg holes are longitudinallydisplaced along said plate portion.
 9. A bone fracture fixation deviceaccording to claim 1, wherein: said peg holes are each oriented in adiscrete direction.
 10. A bone fracture fixation device according toclaim 9, wherein: said peg holes are each perpendicular to alongitudinal axis of said plate portion.
 11. A bone fracture fixationdevice according to claim 9, wherein: said plurality of peg holesincludes exactly first, second, and third peg holes, said first andthird peg holes each being angled approximately 40° relative to saidsecond peg hole.
 12. A bone fracture fixation device according to claim9, further comprising: c) a plurality of pegs, each having a threadedhead portion which is threaded in one of said threaded peg holes.
 13. Abone fracture fixation device according to claim 1, wherein: saidthreaded peg holes includes first, second and third peg holes, saidfirst and third peg holes each being directed 45° relative to saidsecond peg hole.
 14. A bone fracture fixation device according to claim1, wherein: said plate portion includes a peg hole oriented normalrelative to the plate portion.
 15. A bone fracture fixation deviceaccording to claim 1, wherein: said plate portion is longitudinallyoffset relative to said nail portion by a neck portion.
 16. A bonefracture fixation device according to claim 1, wherein: said neckportion has an ‘S’ shape.
 17. A bone fracture fixation device accordingto claim 1, wherein: said flexible section of said nail portion islaterally angled relative to a distal portion of said rigid section ofsaid nail portion.
 18. A bone fracture fixation device for use with aplurality of pegs each having a threaded head portion, said devicecomprising: a) a proximal elongate nail portion; and b) a distalrelatively flat plate portion including a plurality of longitudinallydisplaced threaded peg holes, said peg holes having axes adapted toprovide the pegs inserted into said peg holes in a fanned arrangement.19. A bone fracture fixation device according to claim 18, wherein: saidplate portion is horizontally and vertically offset relative to saidnail portion.
 20. A bone fracture fixation device according to claim 18,wherein: said nail portion includes a flexible section and a rigidsection relatively larger in diameter than said flexible section.
 21. Abone fracture fixation system, comprising: a) a fixation deviceincluding i) a proximal elongate nail portion, and ii) a distalrelatively flat plate portion including a plurality of longitudinallydisplaced peg holes, said plate portion being horizontally andvertically offset relative to said nail portion; b) a plurality of pegsindividually insertable into a respective one of said peg holes, whereinwhen each said peg is inserted into its respective peg hole, said pegcan be oriented in any of several orientations; and c) means for lockingsaid pins in any of its orientations.
 22. A bone fracture fixationdevice according to claim 21, wherein: said nail portion includes aflexible section and a rigid section relatively larger in diameter thansaid flexible section.
 23. A method of treating a metaphyseal bonefracture, the bone having a medullary canal and an exterior, said methodcomprising: a) providing a device having an elongate portion having asubstantially circular cross section which is tapered along its length,and a relatively flat plate portion including a plurality of peg holes,the plate portion being parallel to, but not coaxial with, the elongateportion; b) inserting the elongate portion into the medullary canal; c)stabilizing the plate portion against the exterior of the bone; d)creating holes in the bone in alignment with the peg holes; and e)inserting pegs through the peg holes and into the holes in the bone. 24.A method according to claim 23, wherein: said inserting occurs proximalthe bone fracture, and said stabilizing occurs distal the bone fracture.25. A method according to claim 23, wherein: said elongate portionincludes a screw hole and wherein said method further comprisesinserting a screw through the bone, into the medullary canal, and intothe screw hole.
 26. A method according to claim 23, wherein: said deviceincludes at least one screw hole, and said stabilizing includesinserting a screw through one of said at least one screw hole and intothe bone.
 27. A method according to claim 23, wherein: said elongateportion includes a flexible proximal section and a relatively rigiddistal section, and said inserting includes bending said flexibleproximal section.
 28. A method according to claim 23, furthercomprising: prior to inserting said flexible and rigid sections, makinga notch in said bone at the bone fracture.
 29. A method according toclaim 28, wherein: the device includes a neck portion between saidelongate portion and said plate portion, wherein after inserting saidelongate portion into the medullary canal, said neck portion is seatedin said notch.
 30. A method of treating a distal radius fracture, thedistal radius having a Lister's tubercule on its dorsal side, and amedullary canal, said method comprising: a) providing a device having aplate portion including a plurality of peg holes; b) removing at least aportion of the Lister's tubercule to a relatively lower profile platesurface of the bone; c) positioning the plate portion against the platesurface of the bone; and d) inserting pegs through the peg holes andinto the distal radius bone.